In casting and rolling plants of this type, slabs are processed to form strip material. The known casting and rolling plants comprise at least one casting machine, the slabs of which are fed to at least one tunnel furnace without being temporarily stored. The tunnel furnace opens out into a rolling mill train (finishing train) with at least one rolling stand. In the rolling mill train, the slabs are rolled to form hot strips. On leaving the rolling mill train, the rolled hot strips are fed to at least one cooling section and are wound up onto at least one coiler.
A casting and rolling plant is therefore characterized by coupling of the processes of slab casting and hot rolling, which are decoupled in conventional steel sheet production. Therefore, steel industry plants comprise at least three components, namely the steel works, in which steel is produced from pig iron, the slab production line, which has at least one casting installation (casting machine with downstream tunnel furnace), and the rolling mill train (finishing train). To maximize production, either two casting installations with in each case one casting strand or one two-strand casting installation is used.
In the known casting plants, the rolling capacity of the rolling mill train cannot be fully exploited over the course of time, since the casting capacity (casting speed and casting cross section) of the casting machine(s) cannot be increased beyond certain limits if technical and quality problems are to be avoided. Despite full casting operation, this means that the rolling mill train rolls more quickly than the casting machine or machines are able to supply slabs.
A further reason for the limited production capacity of the known casting and rolling plants is that the two-strand casting installation or the two casting installations for technical reasons cannot produce at certain times, resulting in gaps in production. The unused production gaps include, inter alia, the necessary idle times of the casting machines caused by the need to change the distributor, mold or segment, planned downtimes for maintenance work and unplanned downtimes caused by problems in casting operation. This means that the rolling mill train then either cannot carry out any rolling at all or can only carry out rolling with increased pauses.
Therefore, the two slab production lines constitute a production bottleneck for the capacity of the rolling mill train, leading to a reduced annual production capacity of the casting and rolling plant.